Heat exchanger leak detection using mass gas flow metering

Abstract

Apparatus and methods for detecting leaks in a heat exchangers use mass gas flow metering. A regulated gas supply passes through a mass flow meter before entering either the product chamber or media chamber of a heat exchanger. The regulated gas supply passes into the heat exchanger through an inlet connection. All other inlets and outlets to the testing chamber are closed and isolated so that the chamber holds an applied pressure. The chamber on the opposite side of the heat exchanger is opened to atmosphere. Once gas fills the chamber and a static pressure is realized, the test begins by simply monitoring gas flow. If no flow is indicated, no flow rate is detected, and there is no detectable leak. Gas flow into the test chamber, at any given flow rate, as sensed by the sensitive mass flow meter, is an indication that leakage between the chambers exists.

1. A heat exchanger leak detection apparatus comprising:
 a first inlet stream connected to a first inlet to a heat exchanger, 
 a first outlet stream connected to a first outlet from the heat exchanger, 
 a second inlet stream connected to a second inlet to the heat exchanger, 
 a second outlet stream connected to a second outlet from the heat exchanger, 
 isolation valves on each of the first inlet stream, first outlet stream, second inlet stream, and second outlet stream, 
 a vent in the second outlet stream, 
 a tee in the first inlet stream, 
 a valve in a branch of the tee for isolating a gas supply connected to the branch of the tee, and 
 a mass flow meter between the gas supply and the tee. 
 
   
   
     2. The apparatus of  claim 1 , wherein the heat exchanger leak detection apparatus is connectable to either a product side or a media side of the heat exchanger. 
   
   
     3. The apparatus of  claim 1 , wherein the heat exchanger is a plate heat exchanger. 
   
   
     4. The apparatus of  claim 1 , wherein the vent, the gas supply and the mass flow meter are portable and removable from the heat exchanger leak detection apparatus. 
   
   
     5. The apparatus of  claim 1 , wherein the vent, the gas supply and the mass flow meter are fixed and dedicated to the heat exchanger leak detection apparatus. 
   
   
     6. The apparatus of  claim 1 , wherein the valve in the branch of the tee is a bubble-tight shut-off. 
   
   
     7. The apparatus of  claim 1 , wherein the valve in the branch of the tee is a gasketed blank. 
   
   
     8. The apparatus of  claim 1 , wherein the valve in the branch of the tee is a cap and spool piece connection. 
   
   
     9. The apparatus of  claim 1 , wherein the mass flow meter is a thermal mass meter. 
   
   
     10. The apparatus of  claim 1 , further comprising a rate display and a flow recorder connected to the mass flow meter. 
   
   
     11. The apparatus of  claim 1 , wherein the gas supply comprises helium gas. 
   
   
     12. The apparatus of  claim 1 , further comprising drain valves and corresponding drains along the gas supply, inlet streams and outlet streams. 
   
   
     13. The apparatus of  claim 1 , further comprising sensors along the gas supply, inlet streams and outlet streams. 
   
   
     14. A heat exchanger leak detection method comprising:
 providing a first inlet stream to a first inlet on a heat exchanger and a first outlet stream from a first outlet on the heat exchanger, 
 providing a second inlet stream to a second inlet on the heat exchanger and a second outlet stream from a second outlet on the heat exchanger, 
 providing isolation valves on the first inlet stream, second inlet stream, first outlet stream and second outlet stream, 
 providing a tee between the isolation valve on the first inlet stream the first inlet, 
 providing a valve on a branch of the tee, 
 draining the first inlet stream, second inlet stream, first outlet stream, second outlet stream and heat exchanger of fluids, 
 closing the isolation valves on the first inlet stream, second inlet stream, first outlet stream and second outlet stream, 
 venting the second outlet stream, 
 opening the valve on the tee, 
 flowing gas from a gas supply, through a gas supply stream, through the tee and into the first inlet stream, 
 measuring mass flow rate with a mass flow meter installed between the gas supply and the valve on the tee, and 
 detecting leaks in the heat exchanger. 
 
   
   
     15. The method of  claim 14 , further comprising testing either a product side or a media side of the heat exchanger. 
   
   
     16. The method of  claim 14 , wherein the heat exchanger is a plate heat exchanger. 
   
   
     17. The method of  claim 14 , wherein the vent in the outlet stream, the gas supply, the gas supply stream and the mass flow meter are portable and removable from the heat exchanger leak detection apparatus. 
   
   
     18. The method of  claim 14 , wherein vent in the outlet stream, the gas supply, the gas supply stream and the mass flow meter are fixed and dedicated to the heat exchanger leak detection apparatus. 
   
   
     19. The method of  claim 14 , wherein the mass flow meter is a thermal mass meter. 
   
   
     20. The method of  claim 14 , further comprising displaying a rate and recording flow from the mass flow meter. 
   
   
     21. A heat exchanger leak detection apparatus comprising:
 a connector for connecting to one of the ports of a heat exchanger chamber, 
 isolation valves connected to inlet and outlet ports of one chamber of a heat exchanger, 
 a connector connected to the one chamber between the isolation valves, 
 a main test valve connected to the connector, 
 a test gas supply, 
 a supply valve connected to the supply, 
 a pressure sensor connected to the supply, 
 a mass flow sensor connected to the supply sensing mass flow after the pressure sensor senses a static pressure in the supply, and 
 a display connected to the mass flow sensor. 
 
   
   
     22. The apparatus of  claim 21 , further comprising a pressure regulator connected to the test gas supply. 
   
   
     23. The apparatus of  claim 21 , wherein the heat exchanger leak detection apparatus is permanently connected to a heat exchanger. 
   
   
     24. The apparatus of  claim 21 , wherein the heat exchanger leak detection apparatus is portable and detachably connected to a heat exchanger. 
   
   
     25. A method for testing heat exchangers for leakage comprising:
 isolating a first chamber of a heat exchanger; 
 venting a second chamber of the heat exchanger; 
 draining the first chamber; 
 supplying a test gas under pressure to the first chamber; and 
 measuring the mass flow rate of the test gas with a mass flow sensor. 
 
   
   
     26. The method of  claim 25 , further comprising providing isolation valves on inlet outlet ports of one chamber of the heat exchanger. 
   
   
     27. The method of  claim 26 , further comprising closing the isolation valves supplying the test gas under pressure.